I enjoyed my tour of the cave and I think it's a great attraction, but it wasn't life-changing.
The guided tour has some interesting facts, especially for people with no knowledge of geology. There are perfect examples of several different kinds of formations. The cave has been outfitted with walkways and railings in certain areas to help you discover it without being a crazy adventurer. The temperature is pretty chill, as you'd expect, all year round.
There's a gorgeous aragonite formation at the back of the cave, but it's marred by what I consider to be a slightly silly light show. But this is a great attraction to introduce somebody to the wonder of southern French geology. There are some cool things to look at. Maybe not life changing, but very pretty. And it's a nice way to get out of the heat for a bit.
When I bring people here (I live in the region), I often try to picnic in the mountains nearby.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.